1. Technical Field
This invention relates to an engine control system.
2. Background Art
For better engine operation and for reducing undesirable exhaust gases, it is necessary to control the air fuel ratio. To control this air fuel ratio, a determination of engine load is desirable.
Various measurements of engine load are known, but they can require relatively expensive air flow or air pressure measurement sensors. For example, vane air flow meters and mass air flow meters can be used. Further, these measurements may require a relatively complex electronic engine control system with a relatively large memory which may also add undesirably to engine control system expense.
In particular, it is known to control the fuel supply to an engine as a function of engine speed and throttle angle. Such a system is described in "A New Single Point Fuel Injection System With Adaptive Memory Control to Meet Most Stringent Emission Standards", I Mech E 1985 C221/85 p. 69-75. Nevertheless, more accurate control of engine operation is desirable taking into account more parameters without adding unnecessarily to the expense of manufacturing the engine control system.
Further, such known engine control systems may have various drawbacks such as inaccuracy or excessive cost. It would be desirable to avoid the need for pressure sensors, air flow meters and complex control modules. These are some of the problems this invention overcomes.